Perform the research, development, and evaluation necessary to detect and quantify lesions in coronary arteries of humans using a minimally invasive system which is capable of resolving a 0.5 mm lesion in a coronary artery with a lumendiameter of 2 mm or less. Research and development, in vitro and in vivo studies, and evaluation of human studies will be performed with an improved multiple x-ray tube system - the dynamic spatial reconstructor - in conjunction with intravenous administration of contrast agent.